Normal anatomy and variations in the confluence of sinuses using digital subtraction angiography

The configuration of the confluence of sinuses differs not only between individuals, but also between the two brain hemispheres, making the anatomical classification of this region difficult. In this study, we evaluated the anatomy of the confluence of sinuses and ascertained the accuracy and usefulness of digital subtraction angiography (DSA) in the evaluation of cerebral veins.

Bilateral carotid and vertebral artery angiographies were performed in 500 adult patients to evaluate the anatomy of the confluence of sinuses and contributory venous sinuses. We appraised the anatomy of the sinuses adjacent to the confluence, the lateralization of venous draining into the transverse sinuses (TSs), the communications between the TSs, and the presentation of the occipital sinus (OS).

Based on the anatomical descriptions of Osborn's Brain (Diagnostic Cerebral Angiography, 2nd edition), we delineated 10 different configurations of the confluence of sinuses that showed connections among the superior sagittal sinus, the straight sinus, and the left and right TSs. Right side dominant transverse sinus accounted for 49% of the cases. Direct communication between the TSs accounted for 46.4% of the cases. Indirect communication accounted for 51.6% of the case, and absence of communication between the left and the right TS accounted for 2%. Lastly, the presence of OS was observed in 6% of the cases.

DSA promises to be an effective technique for studying the anatomy and normal variations of the confluence of sinuses, providing useful information for the diagnosis of cerebral venous diseases, and ensuring safer surgical procedures.